<?php
// +----------------------------------------------------------------------
// | ThinkPHP [ WE CAN DO IT JUST THINK IT ]
// +----------------------------------------------------------------------
// | Copyright (c) 2010 http://thinkphp.cn All rights reserved.
// +----------------------------------------------------------------------
// | Licensed ( http://www.apache.org/licenses/LICENSE-2.0 )
// +----------------------------------------------------------------------
// | Author: liu21st <liu21st@gmail.com>
// +----------------------------------------------------------------------
// $Id$

/**
 +------------------------------------------------------------------------------
 * 文件类型缓存类
 +------------------------------------------------------------------------------
 * @category   Think
 * @package  Think
 * @subpackage  Util
 * @author    liu21st <liu21st@gmail.com>
 * @version   $Id$
 +------------------------------------------------------------------------------
 */
class CacheFile extends Cache
{//类定义开始

/**
 +----------------------------------------------------------
 * 架构函数
 +----------------------------------------------------------
 * @access public
 +----------------------------------------------------------
 */
public function __construct($options='')
{
	if(!empty($options['temp'])){
		$this->options['temp'] = $options['temp'];
	}else {
		$this->options['temp'] = C('DATA_CACHE_PATH');
	}
	$this->expire = isset($options['expire'])?$options['expire']:C('DATA_CACHE_TIME');
	if(substr($this->options['temp'], -1) != "/")    $this->options['temp'] .= "/";
	$this->connected = is_dir($this->options['temp']) && is_writeable($this->options['temp']);
	$this->type = strtoupper(substr(__CLASS__,6));
	$this->init();

}

/**
 +----------------------------------------------------------
 * 初始化检查
 +----------------------------------------------------------
 * @access private
 +----------------------------------------------------------
 * @return boolen
 +----------------------------------------------------------
 */
private function init()
{
	$stat = stat($this->options['temp']);
	$dir_perms = $stat['mode'] & 0007777; // Get the permission bits.
	$file_perms = $dir_perms & 0000666; // Remove execute bits for files.

	// 创建项目缓存目录
	if (!is_dir($this->options['temp'])) {
		if (!  mkdir($this->options['temp']))
		return false;
		chmod($this->options['temp'], $dir_perms);
	}
}

/**
 +----------------------------------------------------------
 * 是否连接
 +----------------------------------------------------------
 * @access public
 +----------------------------------------------------------
 * @return boolen
 +----------------------------------------------------------
 */
private function isConnected()
{
	return $this->connected;
}

/**
 +----------------------------------------------------------
 * 取得变量的存储文件名
 +----------------------------------------------------------
 * @access private
 +----------------------------------------------------------
 * @param string $name 缓存变量名
 +----------------------------------------------------------
 * @return string
 +----------------------------------------------------------
 */
private function filename($name)
{
	$name	=	md5($name);
	if(C('DATA_CACHE_SUBDIR')) {
		// 使用子目录
		$dir   ='';
		for($i=0;$i<C('DATA_PATH_LEVEL');$i++) {
			$dir	.=	$name{$i}.'/';
		}
		if(!is_dir($this->options['temp'].$dir)) {
			mk_dir($this->options['temp'].$dir);
		}
		$filename	=	$dir.$this->prefix.$name.'.php';
	}else{
		$filename	=	$this->prefix.$name.'.php';
	}
	return $this->options['temp'].$filename;
}

/**
 +----------------------------------------------------------
 * 读取缓存
 +----------------------------------------------------------
 * @access public
 +----------------------------------------------------------
 * @param string $name 缓存变量名
 +----------------------------------------------------------
 * @return mixed
 +----------------------------------------------------------
 */
public function get($name)
{
	$filename   =   $this->filename($name);
	if (!$this->isConnected() || !is_file($filename)) {
		return false;
	}
	N('cache_read',1);
	$content    =   file_get_contents($filename);
	if( false !== $content) {
		$expire  =  (int)substr($content,8, 12);
		if($expire != -1 && time() > filemtime($filename) + $expire) {
			//缓存过期删除缓存文件
			unlink($filename);
			return false;
		}
		if(C('DATA_CACHE_CHECK')) {//开启数据校验
			$check  =  substr($content,20, 32);
			$content   =  substr($content,52, -3);
			if($check != md5($content)) {//校验错误
				return false;
			}
		}else {
			$content   =  substr($content,20, -3);
		}
		if(C('DATA_CACHE_COMPRESS') && function_exists('gzcompress')) {
			//启用数据压缩
			$content   =   gzuncompress($content);
		}
		$content    =   unserialize($content);
		return $content;
	}
	else {
		return false;
	}
}

/**
 +----------------------------------------------------------
 * 写入缓存
 +----------------------------------------------------------
 * @access public
 +----------------------------------------------------------
 * @param string $name 缓存变量名
 * @param mixed $value  存储数据
 * @param int $expire  有效时间 -1 为永久
 +----------------------------------------------------------
 * @return boolen
 +----------------------------------------------------------
 */
public function set($name,$value,$expire='')
{
	N('cache_write',1);
	if('' === $expire) {
		$expire =  $this->expire;
	}
	$filename   =   $this->filename($name);
	$data   =   serialize($value);
	if( C('DATA_CACHE_COMPRESS') && function_exists('gzcompress')) {
		//数据压缩
		$data   =   gzcompress($data,3);
	}
	if(C('DATA_CACHE_CHECK')) {//开启数据校验
		$check  =  md5($data);
	}else {
		$check  =  '';
	}
	$data    = "<?php\n//".sprintf('%012d',$expire).$check.$data."\n?>";
	$result  =   file_put_contents($filename,$data);
	if($result) {
		clearstatcache();
		return true;
	}else {
		return false;
	}
}

/**
 +----------------------------------------------------------
 * 删除缓存
 +----------------------------------------------------------
 * @access public
 +----------------------------------------------------------
 * @param string $name 缓存变量名
 +----------------------------------------------------------
 * @return boolen
 +----------------------------------------------------------
 */
public function rm($name)
{
	return unlink($this->filename($name));
}

/**
 +----------------------------------------------------------
 * 清除缓存
 +----------------------------------------------------------
 * @access public
 +----------------------------------------------------------
 * @param string $name 缓存变量名
 +----------------------------------------------------------
 * @return boolen
 +----------------------------------------------------------
 */
public function clear()
{
	$path   =  $this->options['temp'];
	if ( $dir = opendir( $path ) )
	{
		while ( $file = readdir( $dir ) )
		{
			$check = is_dir( $file );
			if ( !$check )
			unlink( $path . $file );
		}
		closedir( $dir );
		return true;
	}
}

}//类定义结束
?>